Hurricane Bob: Wikis

  
  

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Hurricane Bob
Category 3 hurricane (SSHS)

Hurricane Bob approaching New England
Formed August 16, 1991
Dissipated August 20, 1991
Highest
winds
115 mph (185 km/h) (1-minute sustained)
Lowest pressure 950 mbar (hPa; 28.05 inHg)
Fatalities 18 direct
Damage $1.5 billion (1991 USD)
$2.4 billion (2009 USD)
Areas
affected
North Carolina, Long Island, Massachusetts, Connecticut, Rhode Island, New Hampshire, Maine, Atlantic Canada
Part of the
1991 Atlantic hurricane season

Hurricane Bob was the second named storm, first hurricane and first major hurricane of the 1991 Atlantic hurricane season. The only hurricane to make U.S. landfall during the 1991 season, Bob brushed the Outer Banks of North Carolina as it moved northward. The storm then struck New England and later Atlantic Canada as a Category 2 hurricane. Bob left eighteen people dead and $2.8 billion dollars (2005 USD) in damage. It is still the most recent hurricane to strike New England, as of 2009; Hurricane Edouard brought hurricane force winds to Nantucket in 1996, but the center itself stayed offshore.[1]

Contents

Meteorological history

Storm path

Hurricane Bob originated from the remnants of a frontal trough to the southeast of Bermuda on August 12. The system tracked towards the southwest and later west towards the Bahamas. By August 15, satellite analysis of the system found a weak low pressure area a couple hundred miles east of the Bahamas.[2] Operationally the system was not declared a tropical depression until 0600 UTC on August 16 after a reconnaissance mission into the storm found a closed circulation and flight level winds of 37 mph (60 km/h).[3] After post-storm analysis, it was determined that the low had developed into a depression around 0000 UTC. Several hours after being designated, the system began to develop convective banding features. Roughly 18 hours after being declared a depression, the National Hurricane Center (NHC) upgraded it to a tropical storm, giving it the name Bob. At this time, Bob was situated roughly 140 mi (225 km) northeast of Nassau, Bahamas. The storm tracked slowly towards the northwest in response to a deep layer mean flow.[2]

A deepening trough over the eastern United States was forecast to turn the storm toward the north on August 16. This turn took place earlier than forecasters anticipated.[4] The storm slowly intensified as convection was displaced from the center of circulation; however, upper-level outflow was well-defined and intensification of the storm was expected as it tracked over the Gulf Stream.[5] Later that day, Bob began to consolidate and a reconnaissance plane recorded hurricane-force winds at 1719 UTC, following this reading, the NHC upgraded the storm to a Category 1 hurricane on the Saffir–Simpson Hurricane Scale.[2] Shortly after, the hurricane began to turn towards the north-northeast in response to a subtropical ridge over the Atlantic and the trough over the southeastern United States.[6]

By August 18, the NHC noted that the hurricane was asymmetrical, having uneven distribution of the wind radii.[7] Later that day, deep convection continued to form and an eye later appeared on satellite imagery. Early the next day, the eye became increasingly defined as the center of Bob passed roughly 35 mi (55 km) from the North Carolina coastline. By 0600 UTC, Hurricane Hunters recorded flight level winds of 140 mph (225 km/h), corresponding to surface winds of 115 mph (185 km/h). At this time, the barometric pressure of the storm also decreased to 950 mbar (hPa; 28.05 inHg), the lowest pressure recorded during the storm. After attaining this intensity, the hurricane tracked quickly northeast at 25 mph (35 km/h), steered by the trough over the southeast United States, an upper-level cutoff low over the Great Lakes Region and the subtropical ridge over the Atlantic.[6]

Hurricane Bob near peak intensity

The track of Bob by August 19 was similar to that of Hurricane Carol in 1954, another major hurricane that impacted New England.[6] Significantly cooler sea surface temperatures in the path of the hurricane resulted in weakening, leading to the eye becoming cloud-filled. Later on August 19, the western portion of the eyewall brushed the eastern tip of Long Island. Around 1800 UTC, the center of Bob made landfall near Newport, Rhode Island with winds of 100 mph (155 km/h), making it a Category 2 hurricane. The storm quickly weakened as it tracked through Rhode Island and Massachusetts before entering the Gulf of Maine. Around 0130 UTC on August 20, the now weakened Tropical Storm Bob made another landfall near Rockport, Maine with winds of 70 mph (110 km/h).[6]

Later on August 20, Bob had crossed through Maine and part of New Brunswick, Canada and entered the Gulf of St. Lawrence. Around 1800 UTC, the former hurricane transitioned into an extratropical cyclone. Early the next day, the storm passed over northern Newfoundland before re-entering the Atlantic Ocean. Rapidly tracking eastward, the storm briefly weakened to the equivalent of a tropical depression on August 22. After the brief weakening, the remnants of Bob turned towards the southeast and slowed. Once more, the extratropical system weakened to the equivalent of a tropical depression; however, it did not re-intensify. The storm slowly tracked towards the east before dissipating off the coast of Portugal on August 29.[6]

Impact

Hurricane Bob brought sustained hurricane force winds to the immediate coastal communities of Rhode Island and most of southeast Massachusetts. Storm surge in Narragansett Bay peaked at 11.5 feet (3.5 m). Strong tropical storm force winds blew across the remainder of the region, with many areas receiving gusts to hurricane force east of the Connecticut River. Wind damage to trees and utility poles was common and resulted in numerous power outages. Over 60 percent of the residents across southeast Rhode Island and southeast Massachusetts lost power. Damage was also extensive to apple and peach orchards across these areas.

Hurricane Bob making landfall on Rhode Island

Coastal communities bore the brunt of the storm, with sustained winds between 83 to 107 mph (172 km/h). Peak wind gusts to 125 mph (201 km/h) were recorded on Cape Cod in the towns of Brewster and Truro, as well as in Wethersfield, Connecticut. The highest sustained wind of 100 mph (160 km/h), was recorded in North Truro. Block Island reported sustained winds of 90 mph (140 km/h), with gusts in excess of 105 mph (maximum speed of equipment). Wind gusts to near 100 mph (160 km/h) were recorded in Newport and by the Navy Ship USS Samuel B. Roberts (FFG-58), which was riding out the storm on the east passage between Newport and Jamestown, Rhode Island. Additionally, six confirmed tornadoes were associated with hurricane Bob; four touched down in North Carolina and two on Long Island, New York. There were 16 unconfirmed tornadoes reported, including nine on Hatteras Island, NC, two in Rhode Island, and two in Massachusetts. The lowest barometric pressure was recorded by the USS Valdez (FF-1096) while in the east passage of Narragansett Bay, with a reading of 28.47 inches (723 mm).

Hurricane Bob caused a storm surge of 6 to 10 feet (above mean tide) along the Rhode Island shore, which would have resulted in four feet of water inundating downtown Providence had its protective hurricane barrier that sheltered it failed.[8] The surge was worse (10 to 15 feet (4.6 m)) in Buzzards Bay. The Buzzards Bay shore east to Cape Cod was hardest hit. The highest surges, of 12 to 15 feet (4.6 m), were observed in Onset, Bourne, and Wareham, at the head of Buzzards Bay. Cove Road, in Mattapoisett, Massachusetts had 29 of 37 homes destroyed, while Angelica Point lost 32 of 35 homes along the shore. Boat damage was significant, as many boats were torn from their moorings. On the portion of the lower Cape Cod, residents were without power for serveral weeks after the storm had passed. Contracted electrical companies from as far away as Canada, were called in to fix down power lines as a result of the storm. Extensive beach erosion occurred along the shore from Westerly, Rhode Island eastward. Some south facing beach locations on Martha's Vineyard and Nantucket Island lost up to 50 feet (15 m) of beach to erosion. Due to the extensive damage, President George H.W. Bush declared Rhode Island a "disaster area" because of Hurricane Bob.

The storm also affected the Canadian Maritimes. Two boys were killed by being swept out to sea. The eye passed directly over Campobello Island, New Brunswick.

Significant rainfall of 3 to 6 inches (150 mm) fell across all but southeast Rhode Island and eastward to Cape Cod, where less than 1-inch (25 mm) fell. The heaviest rainfall of over 7 inches (180 mm) affected western Rhode Island and extreme eastern Connecticut. Portland, Maine had the highest amount of rain with 8.24 inches (209 mm); the 24 hour rainfall associated with Bob set a record for Portland. Its storm total rainfall graphic is located here.

Wind gusts of up to 61 mph (98 km/h) were reported in Portland, Maine. 2.8 feet (0.85 m) storm surge occurred in the Portland Tide Gauge. A total of three fatalities from Bob were reported in Maine. The total damage in Maine topped off at $212 million (1991 USD). Many locations in Maine experienced long-duration power-outages. The Sebago Lake area also reported heavy damage.[9]

It was the strongest hurricane to strike New England since Hurricane Gloria hit on September 27, 1985. Bob was responsible for six deaths in Connecticut, 18 deaths in the United States and for 20 deaths overall. It spawned tornadoes in North Carolina and Long Island. Total damage in southern New England was approximately $1.7 billion ($2.5 billion in 2005 dollars).

Aftermath

Because of its impact, the name Bob was retired in the spring of 1992 and will never be used again for an Atlantic hurricane. It was replaced with "Bill" in the 1997 season.

See also

References

Note: Large amounts of information on this page have been incorporated from NOAA, allowable under United States fair use laws. Original source of the information is at http://www.erh.noaa.gov/er/box/hurricanebob.htm The page has the disclaimer "This information was taken from SOUTHERN NEW ENGLAND TROPICAL STORMS AND HURRICANES, A Ninety-eight Year Summary 1909-1997, by David R. Vallee and Michael R. Dion, National Weather Service, Taunton, MA."

  1. ^ http://www.weathernewengland.com/tim-kelley/new-england-hurricane-history-bob-bill/1004441.html
  2. ^ a b c Max Mayfield (August 10, 1992). "Hurricane Bob Preliminary Report Page One". National Hurricane Center. http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1991-prelim/bob/prelim01.gif. Retrieved August 22, 2009.  
  3. ^ Miles B. Lawrence (August 16, 1991). "Tropical Depression Three Discussion One". National Hurricane Center. http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1991/bob/tropdisc/nal0391.001. Retrieved August 22, 2009.  
  4. ^ Harold P. Gerrish (August 16, 1991). "Tropical Storm Bob Discussion Four". National Hurricane Center. http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1991/bob/tropdisc/nal0391.004. Retrieved August 23, 2009.  
  5. ^ Lixion A. Avila (August 17, 1991). "Tropical Storm Bob Discussion Five". National Hurricane Center. http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1991/bob/tropdisc/nal0391.005. Retrieved August 23, 2009.  
  6. ^ a b c d e Max Mayfield (August 10, 1992). "Hurricane Bob Preliminary Report Page Two". National Hurricane Center. http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1991-prelim/bob/prelim02.gif. Retrieved August 23, 2009.  
  7. ^ Richard Pasch (August 18, 1991). "Hurricane Bob Discussion Ten". National Hurricane Center. http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1991/bob/tropdisc/nal0391.010. Retrieved August 23, 2009.  
  8. ^ http://www.providenceri.com/publicworks/hurricane/significance6.html
  9. ^ [1]

External links

Tropical cyclones of the 1991 Atlantic hurricane season
B
Saffir-Simpson Hurricane Scale
TD TS 1 2 3 4 5

Simple English

Hurricane Bob struck North Carolina and southeast New England during August of the 1991 Atlantic hurricane season. Bob took 15-22 lives and created $1.5 billion in damage. The storm was one of the worst hurricanes to impact the New England during the 20th Century, the 1938 hurricane being the worst of them.








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